Conventionally, a card reader has been known which is provided with a security function structured to detect illegal detachment of the card reader from its host apparatus to prevent illegal acquisition of data (see, for example, Patent Literatures 1 and 2). A card reader described in Patent Literature 1 includes a sheet switch disposed on a front face of the card reader. In this card reader, when the card reader is attached to a host apparatus, a protruded part formed on a rear face side of a front panel of the host apparatus presses the sheet switch and, when the card reader is detached from the host apparatus, the pressed state of the sheet switch is released. Therefore, in this card reader, it can be detected that the card reader has been illegally detached from the host apparatus based on a state of the sheet switch. Further, in this card reader, when it is detected that the card reader has been illegally detached from the host apparatus, a predetermined processing for preventing illegal acquisition of data is executed and illegal acquisition of data from the card reader can be prevented.
A card reader described in Patent Literature 2 includes a tamper switch. The tamper switch includes a tamper member which is formed in a columnar shape and a tamper conduction member which is disposed at a position capable of being pressed by the tamper member. In this card reader, when the card reader is attached to a host apparatus, the tamper member is moved to a side of the tamper conduction member and presses the tamper conduction member and thereby the tamper conduction member becomes an electrically conductive state. Further, when the card reader is detached from the host apparatus, the tamper member is moved in a direction separated from the tamper conduction member and the tamper conduction member becomes a non-conductive state. Therefore, in this card reader, it can be detected that the card reader has been illegally detached from the host apparatus based on a state of the tamper switch. Further, in this card reader, when it is detected that the card reader has been illegally detached from the host apparatus, a predetermined processing for preventing illegal acquisition of data is executed and illegal acquisition of data from the card reader can be prevented.